Z-body, Y-pattern and angle globe valves for throttling, plus control valves with plug, needle and cage-guided trim. Made in Britain by Young & Cunningham, sized, supplied and supported in the GCC by Petromarsh.
Tap a part to see what it does. The blue line shows the S-shaped path: in under the seat, up past the plug, and out the other side.
Handwheel or actuator. A handwheel for manual valves. For control duty a pneumatic diaphragm or piston actuator moves the stem, driven by a positioner that takes a 4–20 mA or digital signal from the control system.
Stem. Moves the plug straight up and down. The stroke is short, so a globe valve opens and closes faster than a gate valve of the same size.
Bonnet and yoke. The bonnet closes the top of the body and guides the stem. Extended bonnets keep the packing away from very hot or cryogenic fluid.
Packing. Graphite or PTFE rings around the stem. Control valves move all day, so low-friction, low-emission packing matters more here than on an isolation valve.
Disc or plug. The closing member. Its shape sets how flow changes with lift: a flat disc for on-off, a contoured plug for linear or equal percentage control.
Seat ring. The ring the plug closes onto, often screwed in or clamped so it can be replaced. Hard-faced or hardened for erosive and high-pressure-drop duty.
Body. An internal wall turns the flow twice, so the fluid passes up through the seat. This gives good control and tight shut-off, at the cost of a higher pressure drop than a gate or ball valve.
A globe valve closes by pushing a disc or plug straight down onto a seat. The flow passes through the seat opening, so the gap between plug and seat sets the flow rate. This makes it the natural valve for throttling, and the base of most control valves.
The plug moves in line with the flow through the seat. A small lift gives a small, stable flow. The flow changes smoothly with stem position, which is what control needs.
The fluid turns twice inside the body. That costs pressure drop, so globe valves are not used where a free, full bore is needed. Y-pattern and angle bodies reduce the loss.
Add an actuator and a positioner, and the globe valve becomes a control valve. It holds a flow, pressure, level or temperature at the set point from the control system.
A globe valve is defined by its body pattern, which sets the flow path, and its trim, which sets how it closes and controls. Tap a type to see where it fits.
Inlet and outlet in line, with an internal wall that forms a Z or S path. Compact and easy to service through the bonnet, it is the most common globe body.
Used across GCC plants for bypasses, drains and manual throttling.
The seat and stem sit at an angle to the pipe, so the flow turns less. Pressure drop is lower and the body can be rodded out, which suits high-pressure steam and erosive service.
Common on high-pressure steam, boiler blowdown and feed water in power and desalination plants.
Inlet and outlet at right angles. The valve also replaces an elbow, and the single turn gives less pressure drop than a Z-body. Often used where flashing or solids would wear a straight body.
Used for wellhead chokes, high-pressure letdown and tank bottom drains.
A flat or conical disc gives on-off and rough throttling. A contoured plug shapes the flow curve: linear, or equal percentage where each step of lift changes flow by the same percentage. Seats can be metal or soft.
Chosen on the control valve datasheet from the process loop and the pressure drop available.
A slim tapered needle in a small seat. Many turns move the needle a little, so very small flows can be set accurately. Usually small bore, forged and threaded or socket-welded.
Found on instrument manifolds, sample points and chemical injection lines.
The plug slides inside a cage with shaped windows. The cage guides the plug, sets the flow curve and can split the flow into many small jets to cut noise and cavitation. Trims are changed without changing the body.
The usual trim for control valves on gas, steam and hydrocarbon service in GCC process plants.
Throttling puts the trim in the fastest, most erosive part of the flow. Body material follows the piping class. Trim and seat material follow the pressure drop, the fluid and the risk of cavitation or flashing.
| Part | Carbon and low-temp steel | Stainless and duplex | Bronze and special alloys |
|---|---|---|---|
| Body and bonnet | Cast or forged carbon steel, chrome-moly for hot steamA216 WCB · A105 · A217 WC6 · A352 LCC | 316 stainless, duplex and super duplexA351 CF8M · A182 F316 · A995 4A / 5A | Bronze, aluminium bronze and cast iron for water and marine dutyB62 · B148 C95800 · A126 |
| Plug and seat | 13% chrome, hardened410 · 416 SS | 316 with Stellite facing for high pressure drop316 + CoCr hard-facing | Tungsten carbide or ceramic for severe erosionsolid or overlay |
| Packing and gaskets | PTFE V-rings for control duty, graphite for high temperature, low-emission sets where requiredISO 15848-1 · ASME B16.20 | ||
Manual globe valves follow the valve codes. Control valves add sizing, leakage and actuator standards. Your datasheet names which apply.
Steel globe and globe stop and check valves for petroleum and process duty. BS EN 13709 replaced BS 1873, which is still quoted on many datasheets.
Bolted bonnet steel globe valves for petroleum and gas service, the American equivalent of BS 1873.
Pressure and temperature ratings, wall thickness and materials for steel valves.
Control valve sizing (Cv and Kv), noise prediction, inspection and testing, in several parts.
Control valve seat leakage classes I to VI. Class VI is the bubble-tight soft-seat class.
Face-to-face lengths for globe valves. Control valves follow ISA 75.08 or IEC 60534-3.
Shell, back seat and seat leak tests for manual globe valves.
Stem seal leakage type testing, important for control valves that stroke all day.
Material and hardness limits for hydrogen sulphide service.
Your engineers red-line our drawings, you approve the design twice before production starts, and you can witness the tests. Tap a step to see what happens and which documents you receive.
Young & Cunningham has made valves in Britain since the 1920s, with a long history of supplying the UK Ministry of Defence. They make straight and right-angle globe valves, including screw-down non-return designs, and supply actuated valves for automation. Petromarsh, their exclusive representative in the GCC, adds control valve sizing, management and testing.
For a manual valve, size, class and materials are enough. For a control valve, the process data on the right lets us size the trim and reply with a proposal.
